The present invention relates generally to the field of modulating flow separation and more specifically to the use of a pulse detonation actuator (PDA) for injecting fluid into a boundary layer of an aerodynamic surface.
In a wide variety of applications, aerodynamic surfaces are used to manipulate the speed and pressure of moving fluids. Examples of aerodynamic surfaces include, but are not limited to, airfoils and channel surfaces. Examples of airfoils include, without limitation: aircraft wings; rotor blades for propellers, fans, compressors, turbines, helicopters, and other rotorcraft; and stator vanes for compressors and turbines. Examples of channel surfaces include, without limitation, diffusers for gas turbine engines.
Many aerodynamic surfaces are designed to create an adverse pressure gradient, i.e., a region wherein pressure increases along the direction of flow. Such an adverse pressure gradient may cause the fluid boundary layer to separate from the aerodynamic surface thereby reducing the efficacy of the design.
One strategy for reducing the tendency toward boundary layer separation is to inject fluid into the boundary layer through jets in the aerodynamic surface. Typically, the effectiveness of this strategy increases as the velocity of the injected fluid approaches the velocity of the bulk fluid flow. Conversely, applicability of the strategy is conventionally limited by the pressure rise and velocity increase for fluid injection producible by conventional means.
A pulse detonation actuator (PDA) provides a means for creating a pressure rise and velocity increase greater, in some applications, than the pressure rise and velocity increase available for boundary layer fluid injection by conventional means. Opportunities exist, therefore, to broaden the applicability of boundary layer fluid injection through the use of PDAs.